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Excessive Heeling and Rounding Up (further question)

Posted: Fri Sep 30, 2005 8:09 pm
by Jim Cate
The extended discussion of this subject several months ago included lots of helpful information, some of which I have used on our 26M to minimize rounding up. (Reducing rake by tightening the forestay and loosening the rear-side stays seemed to help quite a bit.)

However, I have a stupid question that wasn't addressed in the previous discussion. - Would it be possible to achieve a similar result (reduce rounding up) by shifting the COG of the boat forwardly? For example, would placing a weight in the bow, or moving cargo forwardly in the boat, tend to pitch the boat forwardly slightly and therefore move the sails and the center of effort forwardly relative to the CLR, therefore producing an effect somewhat similar to reducing rake?

If so, this might provide a secondary adjustment technique that could be made fairly conveniently while under way or sailing. For example, on our boat most of the "cargo" (crew, motor, ice chest, gas tank, etc.) are positioned at or fairly near the stern, while there is normally very little cargo midship or toward the bow. So, it would seem possible that weights, or a sack of gravel, or whatever could be placed under the forward berth, for example, to shift the cg forward slightly. - Obviously, this shouldn't be overdone, and the optimum weight and weight position would have to be determined, but it would have the advantage that the placement of the weight could be adjusted fairly easily on the water as desired or when conditions changed, assuming that you have a reasonably cooperative crew (or an autopilot).

I would be interested in knowing whether anyone has been able to improve sailing performance (relative either to pointing or other points of sail) or motoring performance by such a technique, or by simply adjusting the position of cargo, etc. In this vein, is it preferable that the boat be pefectly level fore-to-aft, pitched slightly forwardly, or pitched slightly rearwardly?

Jim Cate

:macm:

Posted: Sat Oct 01, 2005 3:24 am
by Catigale
JIm..Im an upper Hudson River sailor, where you dont get a long run very often..

When I cruised the Cape this summer, and was out on open water, we used the vberth to store all our gear ( family of four) and I noticed the boat sailed better than ever. The Admiral assured me it was my skills,but I think the weight shift helped a lot.

havent been quantitative about it though.

Posted: Sat Oct 01, 2005 7:38 am
by baldbaby2000
I did some experimenting while racing on Lake of the Woods. We were on a close reach and one of us moved forward to get the transom farther out of the water. This seemed to help the speed. This technique is mentioned in the Macgregor manual and it makes sense when one looks at "real" sailboat transoms; the flat part of the transom is usually not in the water. I haven't tried it to help rounding up but it sounds like a good experiment.

BB

Excessive Heeling

Posted: Mon Oct 03, 2005 12:44 pm
by Francis
When I sail I usually have two icechest in the isle on the deck as far forward as possible and the other one right behind it. I keep the weight low and forward and it seems to work well. When people talk about rounding up in strong winds and such, I seem to usually hold the course, or at least I do not seem to round up like people are saying. I don't know abut speed or such, but it sure seem like the boat seems to operate a little better. The only thing is, is that you have to walk over the icechests to go back and forth, but that is just part of the deal. I also keep the extra anchor up forward as well. So I would have to say that it does seem to work, or at least for me it does.

Posted: Fri Oct 07, 2005 8:32 am
by normo
In my opinion the roundup problem is inherent with the hull design and sail plan of the Mac. The only way I have found to minimize it is to have good sails, don't trim the main too close to the centerline, reduce sail sooner rather than later and trim and ease the main quickly in gusts. On the X raising the centerboard helps. I doubt that changing fore and aft CG will provide a noticeable improvement for the roundup problem.

Boats that drag the stern like the Macs, Catalina 22/25 benefit from moving weight forward in some conditions. Downwind it is beneficial to move weight forward to get as much of the transom as possible out of the water. Having said this, the improvement is slight and for a boat like the Mac I'm not sure it makes sense to make the interior space unusable by cramming the aisle and dinette with heavy stuff that will have to be moved often.

I would recommend against adding ballast like gravel. Invite Bubba and his twin brother for a sail and have them move about while you check the change in performance. I suspect you will be disappointed.

The boat is what it is and it will never behave like a similar sized keel boat.

Moving weight forward

Posted: Thu Nov 17, 2005 9:39 pm
by Newell
I have been active in the technique's considered on the old Sailnet List to be effective for reducing weather helm, improvements in pointing and speed upwind on the X. I have my batteries (2) at the very front of the V on top of the ballast tank, followed by a 26 gal. water bladder. My mast has been straight up for 5 or 6 years. This year I removed my furler and converted to hank on sails. I have very slight weather helm and only experience roundups in extreme conditions, gusts above 25 mph.

This being said I don't consider that my boat points much better or is much faster. I have won a few races on Lake Mead, NV but have never won in San Diego after 6 trys against other Xs & 1 M. Surprisingly I like the hank on sails and I think there was a speed improvement.

I am currently moving my mast about 1.5 degrees to see if it helps any with pointing.

:?

Moving weight forward

Posted: Thu Nov 17, 2005 9:40 pm
by Newell
Removed duplicate post.

Posted: Fri Nov 18, 2005 1:41 am
by James V
There is a differance in the bow configurations between the :macm: and the :macx: . The manual recomends to not put the bow to deep into the water as it will affect going through the waves. Does anybody know if the :macm: sails better in the waves by having the bow higher or lower?

Is there a "best" position?

Posted: Fri Nov 18, 2005 7:23 am
by Frank C
The storied "rounding up" problem applies mainly to the 26X. It's not clear that the M suffers to the same degree ... guess still an unknown. However, the 26X problem only applies in very strong winds.

Those who sail the 26X in less than 15 knot winds might never see a problem. Those in consistently higher winds will recognize the weather helm immediately, almost like suffering a front blowout on a car. This is especially true for those mountain lakes where a microburst is frequent, though I've never faced that problem. But I assure you that the X can make you feel foolish when Bay winds are steady at 15, and then you sail into a strong gust.

Agree too, with the notes above about moving ballast forward. The best way to habitually load stores forward for sailing in the X ... and never stow heavy loads in the aft berth ... for several reasons. First, your active ballast (crew) will usually be aft, anyhow. Next, your fuel load is ALWAYS aft. Finally, when you invite the neighbors, you compound this natural tendency. Therefore, all normal loading (especially heavy stuff like water, tools & spare equipment) need standard stowage in the forward holds.

Shifting crew forward is a technique for adding a little speed when running, but it's probably counter-productive when sailing upwind. Also, it's a natural change when you send someone to the mast to hold a pole on the Genny ... which IS more effective with that crew on the bow than just the pole without a crew member.

Finally, I don't believe that moving stores forward has a significant impact on the actual mast rake ... you need to shorten the forestay by 4 inches to accomplish a change of 2 degrees ... yet I doubt you can effect even a one-inch waterline change by shifting weight.
FWIW ... fair winds! 8)

Posted: Mon Feb 13, 2006 10:14 am
by Octaman
Hi guys,

I tend to agree with normo's posting; very well said normo!

Might I add ....

Helming is very critical in such 'extreme' situations. The natural, human response of someone at the wheel is to over steer. This results in stalled rudders and rounding up sooner/faster than you normally would.

You have to be a bit more sensitive with the wheel. This comes with experience.

Occassionally, look back and down and visually check rudder angle as the wheel can be deceiving. I am sure you have found yourself in a situation where you are trying to steer more to starboard (for example) only to realize after a while that the wheel won't budge only because you already are all the way to starboard :!:

As for weight distribution; if you can secure more stuff on the windward side of the boat, it will surely make a difference. That is easier said than done belowdecks. On deck; try to keep yourself and your crew seated on the windward side of the cockpit at all times.

Happy Sailing

Octaman 8)

Posted: Mon Feb 13, 2006 10:31 am
by Octaman
James V

If we compare the X to the M, I believe what makes the M sail better in waves is the shape of the hull and the finer bottom shape due to lack of the big keel housing.
(I have no experience on the X; only on the M)

Remeber the X has a deadrise of 7 or 8 degrees (if I recal well) and the M has 15 degrees :!:
This alone makes the M more efficient in waves.

As for burying the bow or not; NOT is the answer on any boat sailing into the wind in a chop.
Having weight on the ends of a boat is detrimental to performance. If you can concentrate all weight to the centre and low down you will have better performance.

As an example, if I am going out in a chop, I take the anchor, chain and rode out of the anchor locker and temporarily store belowdecks in one of the windward stowage spaces the boat has.

It makes a difference.

Happy sailing!

Octaman 8)

Posted: Tue Feb 14, 2006 8:27 pm
by baldbaby2000
Having weight on the ends of a boat is detrimental to performance. If you can concentrate all weight to the centre and low down you will have better performance
When I sailed scows we would try to keep the crew weight close together and towards the center for this reason. It always helped to have one of the crew be a babe for more incentive!